Bonding method of semiconductor chip and bonding apparatus of semiconductor chip

ABSTRACT

A mounting apparatus of a chip including a mechanism configured to arrange a front surface of a chip and a front surface of a substrate to face each other such that a back surface of the chip is attached to a sheet, the sheet having a first portion corresponding to the selected chip and a the second portion arranged at a periphery of the first portion corresponding to the selected chip in the sheet when seen in a direction perpendicular to the front surface of the substrate; a holding mechanism moving in a direction that is not perpendicular to the front surface of the substrate and arranged to hold the second portion of the sheet; and a pushing mechanism for pushing the back surface of the chip through the first portion of the sheet so that the front surface of the chip is brought close to the front surface of the substrate with the first portion deformed in a state where the second portion is held by the holding mechanism, and configured to release the pushing mechanism from the first portion of the sheet to strip the sheet from the back surface of the chip.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. Ser. No.14/710,070, filed May 12, 2015, which is based upon and claims thebenefit of priority from Japanese Patent Application No. 2014-221907,filed on Oct. 30, 2014, the entire contents of both of which areincorporated herein by reference.

FIELD

Embodiments described herein relate generally to a bonding method of asemiconductor chip and a bonding apparatus of the semiconductor chip.

BACKGROUND

A semiconductor chip is mounted and bonded on a substrate to obtain asemiconductor device. In this case, the semiconductor chip is desirablymounted on the substrate while suppressing thermal deformation of thesemiconductor chip and suppressing position shift in the bonding thatoccurs from the difference in the coefficients of thermal expansion ofthe semiconductor chip and the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1G are cross-sectional views illustrating a bonding methodof a semiconductor chip according to an embodiment;

FIG. 2A is a cross-sectional view illustrating a configuration of abonding apparatus of the semiconductor chip according to the embodiment;

FIG. 2B is a bottom view of a pushing head in the bonding apparatusaccording to the embodiment;

FIGS. 3A to 3C are cross-sectional views illustrating a bonding methodof the semiconductor chip according to the embodiment;

FIGS. 4A to 4C are cross-sectional views illustrating the bonding methodof the semiconductor chip according to the embodiment;

FIGS. 5A to 5D are cross-sectional views illustrating the bonding methodof the semiconductor chip according to the embodiment;

FIGS. 6A to 6D are explanatory views illustrating a mechanism of plasmaactivated bonding according to the embodiment; and

FIGS. 7A to 7D are cross-sectional views illustrating a bonding methodof a semiconductor chip according to a variant of the embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided a bondingmethod of a semiconductor chip. The bonding method includes arranging anactivated front surface of a semiconductor chip and an activated frontsurface of a substrate so as to face each other with a back surface ofthe semiconductor chip attached to a sheet. The bonding method includespushing the back surface of the semiconductor chip through the sheet toclosely attach the activated front surface of the semiconductor chip andthe activated front surface of the substrate. The bonding methodincludes stripping the sheet from the back surface of the semiconductorchip while maintaining the state in which the activated front surface ofthe semiconductor chip is closely attached to the activated frontsurface of the substrate.

Exemplary embodiments of a bonding method of a semiconductor chip willbe explained below in detail with reference to the accompanyingdrawings. The present invention is not limited to the followingembodiments.

Embodiment

A bonding method of a semiconductor chip according to an embodiment willbe described. The bonding method of the semiconductor chip is a methodfor mounting a semiconductor chip on a substrate.

For example, a plurality of chips needs to be stacked in a packagingstep of a device to obtain a stacked type device. In this case, if chipsof different chip sizes coexist in a plurality of chips to be stacked,it is difficult to first bond two substrates and then collectivelysingulate the substrates to obtain the stacked type device. Thus, onesubstrate (semiconductor substrate) of the two substrates first needs tobe singulated to a plurality of semiconductor chips, and then thesemiconductor chips need to be mounted on the other substrate.

Alternatively, an optical element needs to be stacked on a templatesubstrate to obtain an optical device. In this case, if substrate sizesof a substrate for the optical element to be singulated to a pluralityof optical elements and a substrate for the template substrate to besingulated to a plurality of template substrates are different, auseless region that does not contribute to obtaining the optical deviceforms when the two substrates are bonded. Thus, one substrate(semiconductor substrate) for the optical element of the two substratesneeds to be first singulated to a plurality of semiconductor chips, andthen the chips need to be mounted on the other substrate.

Consider a case of interposing a solder bump between a pad electrode ofthe semiconductor chip and a pad electrode of the substrate forconduction.

In this case, the semiconductor chip and the substrate need to be heatedto a high temperature (e.g., 350 to 400° C.) to solder bond the solderbump to each of the pad electrode of the semiconductor chip and the padelectrode of the substrate, and hence there is a possibility thesemiconductor chip and the substrate may thermally deform. If thesemiconductor chip and the substrate are made from materials ofdifferent coefficients of thermal expansion, the alignment accuracy inthe bonding of the pad electrode of the semiconductor chip and the padelectrode of the substrate may lower and the electrodes may not beconducted if the semiconductor chip and the substrate are thermallydeformed.

In the present embodiment, as illustrated in FIG. 1 to FIG. 5, thesemiconductor chip is mounted at a normal temperature on the substrateby plasma activated bonding of the semiconductor chip to the substrate.In other words, the semiconductor chip is temporarily bonded at a normaltemperature on the substrate by activating the front surface of thesemiconductor chip and the front surface of the substrate by plasma andclosely attaching the semiconductor chip to the substrate. Thereafter,the semiconductor chip is heated and pressurized to be actually bondedto the substrate. The bonding position of the semiconductor chip on thesubstrate can be substantially fixed with the temporary bonding, andhence the alignment accuracy in the bonding of the semiconductor chipcan be easily enhanced in the actual bonding.

It should be noted that, if electrical conduction is required betweenthe semiconductor chip and the substrate as in the bonding of thesemiconductor chip and the substrate using the solder bump describedabove, a conductor electrode may be arranged on a part of the respectivefront surface of the semiconductor chip and the substrate to beactivated, and the conductors may be electrically connected apart fromthe bonding by the plasma activation. For example, a solder electrodesurrounded by an insulating film (silicon dioxide film) is prepared onthe front surface in each of the semiconductor chip and the substrate.The insulating films in each of the semiconductor chip and the substratemay be bonded and then heated to melt the solder electrodes thus bondingthe solder electrodes.

FIGS. 1A to 1G, FIGS. 3A to 3C, and FIGS. 4A to 4C are stepcross-sectional views illustrating a bonding method of the semiconductorchip. FIG. 2A is a cross-sectional view illustrating a configuration ofa bonding apparatus of the semiconductor chip. FIG. 2B is a bottom viewof a pushing head in the bonding apparatus.

It should be noted that, the activation in the plasma activated bondingrefers to terminating the front surface of the semiconductor chip andthe front surface of the substrate with a hydroxyl group to realize astate in which water molecules can be easily bonded. The plasmaactivated bonding is also sometimes referred to as oxide bonding, fusionbonding, spontaneous bonding, or the like.

In the bonding method of the semiconductor chip, the steps illustratedin FIGS. 1A to 1D and the steps illustrated in FIGS. 1E to 1G arecarried out in parallel as a pre-process of the temporary bonding in theplasma activated bonding.

In the step illustrated in FIG. 1A, a semiconductor substrate 10 to besingulated to a plurality of semiconductor chips 11-1 to 11-6 (see FIG.1B) is prepared. A portion (excluding a pad electrode) in the vicinityof a front surface 10 a in the semiconductor substrate 10 is made of amaterial having any one of silicon, silicon oxide, III-V groupsemiconductor, and an oxide of the III-V group semiconductor as a maincomponent. If the portion in the vicinity of the front surface 10 a inthe semiconductor substrate 10 is made of a material having the siliconoxide as the main component, a region deeper than the portion in thevicinity of the front surface 10 a in the semiconductor substrate 10 maybe made of a material having the silicon as the main component or amaterial having the III-V group semiconductor as the main component. Ifthe portion in the vicinity of the front surface 10 a in thesemiconductor substrate 10 is made of a material having the oxide of theIII-V group semiconductor as the main component, the region deeper thanthe portion in the vicinity of the front surface 10 a in thesemiconductor substrate 10 may be made of a material having the III-Vgroup semiconductor as the main component. The III-V group semiconductorincludes, for example, InP, GaAs, and GaN.

The front surface 10 a in the semiconductor substrate 10 can haveplanarity of smaller than or equal to 1 nm, and more preferably, smallerthan or equal to 0.3 nm. If the planarity of the front surface 10 a issmaller than or equal to 0.3 nm, the planarity of a front surface 11 aof each singulated semiconductor chip 11 also becomes smaller than orequal to 0.3 nm. If the planarity of the front surface 11 a of eachsemiconductor chip 11 is smaller than or equal to 0.3 nm, a void (airgap) forms at a bonding interface when the semiconductor chip 11 istemporarily bonded to the substrate 20 in the step (step illustrated inFIG. 5D) of the actual bonding, and the bonding strength of the actualbonding can be suppressed from not meeting the required strength.

For example, the planarity of the front surface 10 a can be made tosmaller than or equal to 1 nm or can be made to smaller than or equal to0.3 nm by polishing the front surface 10 a of the semiconductorsubstrate 10 through the CMP method, and the like.

Next, a back surface 10 b of the prepared semiconductor substrate 10 isattached to a front surface 1 a of an adhesive sheet (dicing tape) 1. Inother words, the semiconductor substrate 10 is attached to the adhesivesheet 1 with the front surface 10 a exposed (face-up state). Theadhesive sheet 1 has an adhesive applied on the front surface 1 a. Theadhesive may be an adhesive having UV curability, for example. Theadhesive sheet 1 is stretched within a frame of an annular flat ring 2and fixed to the flat ring 2. The adhesive sheet 1 is formed, forexample, with a transparent resin having light permeability.

In the step illustrated in FIG. 1B, the semiconductor substrate 10 isdivided to be singulated into the plurality of semiconductor chips 11-1to 11-6. For example, the semiconductor substrate 10 is dicing processedalong a dicing line. The dicing processing may be carried out by cuttingwith a dicing blade along the dicing line. In this case, the cutting maybe carried out with the dicing blade while introducing water jet, formedby thinly injecting water, to a cutting area. Cutting scraps (particles)thus can be prevented from attaching to the front surface 11 a of thesemiconductor chip 11. Alternatively, the dicing processing may becarried out by emitting a laser along the dicing line and performinglaser processing.

Thereafter, UV irradiation may be carried out on the adhesive sheet 1from the back surface 1 b side to cure the adhesive applied on the frontsurface 1 a of the adhesive sheet 1, thus lowering the adhesion forcethereof.

Furthermore, washing (e.g., ultrasonic washing) and drying processes aresequentially carried out on the front surface 11 a of each semiconductorchip 11 with each semiconductor chip 11 attached to the adhesive sheet1. If the particles are attached to the front surface 11 a of eachsemiconductor chip 11, the attached particles thus can be removed.

In the step illustrated in FIG. 1C, an interval of the plurality ofsemiconductor chips 11-1 to 11-6 on the adhesive sheet 1 is widened.

For example, the adhesive sheet 1 is once detached from the flat ring 2,and then the adhesive sheet 1 is pulled to spread toward the peripherywith the plurality of semiconductor chips 11-1 to 11-6 attached thereto.The interval of the adjacent semiconductor chips 11-1 to 11-6 thus canbe widened.

At this time, as illustrated in FIG. 1C, the interval of the adjacentsemiconductor chips 11-1 to 11-6 can be widened to greater than thethickness of each semiconductor chip 11. If the interval of the adjacentsemiconductor chips 11-1 to 11-6 is smaller than or equal to thethickness of each semiconductor chip 11, a side surface 11 c of thesemiconductor chip 11 to be pushed makes contact with a side surface 11c of the adjacent semiconductor chip 11 and may possibly produceparticles in the step (step illustrated in FIG. 5A) of pushing thesemiconductor chip 11 through the adhesive sheet 1. If the producedparticles are attached to the surface to be temporarily bonded, a void(air gap) having the particle as the starting point forms at the bondinginterface when the semiconductor chip 11 is temporarily bonded to thesubstrate 20, and the bonding strength of the temporary bonding may notmeet the required strength. For example, if a particle having a diameterof 1 μm is interposed at the bonding surface, there is a possibility avoid having a width in the direction along the bonding interface ofabout 1000 μm may form.

In the step illustrated in FIG. 1D, the front surfaces 11 a of theplurality of semiconductor chips 11-1 to 11-6 are collectivelyactivated. For example, the flat ring 2, to which the adhesive sheet 1attached with the plurality of semiconductor chips 11-1 to 11-6 arefixed, is mounted on a stage in a processing chamber of a plasmaprocessing device (not illustrated). In this case, the front surface 11a of each semiconductor chip 11 is facing the upper side. When plasmaPL1 is irradiated onto the front surfaces 11 a of the plurality ofsemiconductor chips 11-1 to 11-6 under depressurization, the frontsurface 11 a of each semiconductor chip 11-1 to 11-6 is activated.Thereafter, the flat ring 2, to which the adhesive sheet 1 attached withthe plurality of semiconductor chips 11-1 to 11-6 are fixed, is conveyedout to the exterior of the processing chamber.

Contaminated objects such as organic substances, and the like attachedto the front surface 11 a of each semiconductor chip 11 thus can beremoved, and the front surface 11 a can be terminated with the hydroxylgroup. For example, a portion (excluding the pad electrode) in thevicinity of the front surface 11 a of each semiconductor chip 11 is madefrom a material having any one of the silicon, the silicon oxide, theIII-V group semiconductor, and the oxide of III-V group semiconductor asthe main component. In any case, the front surface 11 a can be activatedand the front surface 11 a can be terminated with the hydroxyl groupaccording to the step illustrated in FIG. 1C.

It should be noted that, the front surface 11 a of each semiconductorchip 11 may be activated by irradiating the front surface 11 a of eachsemiconductor chip 11 with an energy beam (bombardment) of atoms such asAr, and the like or ions, instead of irradiating the front surface 11 aof each semiconductor chip 11 with the plasma.

In the meantime, in the step illustrated in FIG. 1E, a substrate 20 onwhich the semiconductor chip 11 is to be mounted is prepared. Thesubstrate 20, for example, includes a semiconductor substrate or a glasssubstrate. If the substrate 20 is the semiconductor substrate, a portion(excluding the pad electrode) in the vicinity of a front surface 20 a ofthe substrate 20 is made of a material having any one of the silicon,the silicon oxide, the III-V group semiconductor, and the oxide of theIII-V group semiconductor as the main component. If the portion in thevicinity of the front surface 20 a in the substrate 20 is made of amaterial having the silicon oxide as the main component, a region deeperthan the portion in the vicinity of the front surface 20 a in thesubstrate 20 may be made of a material having the silicon as the maincomponent or a material having the III-V group semiconductor as the maincomponent. If the portion in the vicinity of the front surface 10 a inthe semiconductor substrate 10 is made of a material having the oxide ofthe III-V group semiconductor as the main component, a region deeperthan the portion in the vicinity of the front surface 10 a in thesemiconductor substrate 10 may be made of a material having the III-Vgroup semiconductor as the main component. The III-V group semiconductorincludes, for example, InP, GaAs, and GaN. If the substrate 20 is theglass substrate, a portion (excluding the pad electrode) in the vicinityof the front surface 20 a in the substrate 20 is made of a materialhaving the silicon oxide or a sapphire as the main component, forexample.

The front surface 20 a in the substrate 20 can have planarity of smallerthan or equal to 1 nm, and more preferably, smaller than or equal to 0.3nm. If the planarity of the front surface 20 a is smaller than or equalto 0.3 n, a void (air gap) forms at a bonding interface when thesemiconductor chip 11 is temporarily bonded to the substrate 20 in thestep (step illustrated in FIG. 5D) of the actual bonding, and thebonding strength of the actual bonding can be suppressed from notmeeting the required strength.

For example, the planarity of the front surface 20 a of the substrate 20can be made to smaller than or equal to 1 nm or can be made to smallerthan or equal to 0.3 nm by polishing the front surface 20 a of thesubstrate 20 through the CMP method, and the like.

Furthermore, the washing (e.g., ultrasonic washing) and drying processesare sequentially carried out on the front surface 20 a of the preparedsubstrate 20. If particles are attached to the front surface 20 a of thesubstrate 20, the attached particles thus can be removed.

In the step illustrated in FIG. 1F, the front surface 20 a of thesubstrate 20 is activated. For example, the substrate 20 is mounted on astage in a processing chamber of a plasma processing device (notillustrated) such that the front surface 20 a is facing the upper side.When plasma PL2 is irradiated onto the front surface 20 a of thesubstrate 20 under depressurization, the front surface 20 a of thesubstrate 20 is activated. Thereafter, the substrate 20 is conveyed outto the exterior of the processing chamber.

Contaminated objects such as organic substances, and the like attachedto the front surface 20 a of the substrate 20 thus can be removed, andthe front surface 20 a can be terminated with the hydroxyl group. Theportion (excluding the pad electrode) in the vicinity of the frontsurface 20 a of the substrate 20 is made of a material having any one ofthe silicon, the silicon oxide, the III-V group semiconductor, and theoxide of III-V group semiconductor as the main component. In any case,the front surface 20 a can be activated and the front surface 20 a canbe terminated with the hydroxyl group according to the step illustratedin FIG. 1F.

Furthermore, the washing (e.g., ultrasonic washing) and drying processesare sequentially carried out on the front surface 20 a of the substrate20 in the step illustrated in FIG. 1G. If the particles are attached tothe front surface 20 a of the substrate 20, the attached particles thuscan be removed.

In the bonding method of the semiconductor chip, the temporary bondingin the plasma activated bonding is carried out.

When temporarily bonding the semiconductor chip 11 to the substrate 20,assume a case of picking up each semiconductor chip 11 and detachingfrom the adhesive sheet 1, and mounting each semiconductor chip 11 onthe substrate 20. In this case, a part of the semiconductor chip 11 maychip and produce particles when the front surface 11 a or the sidesurface 11 c of the semiconductor chip 11 is touched, and such producedparticles may attach to the front surface 11 a of the semiconductor chip11. If the produced particles are attached to the front surface 11 a, avoid (air gap) having the particle as the starting point may form at thebonding interface when the semiconductor chip 11 is temporarily bondedto the substrate 20, and the bonding strength of the temporary bondingmay not meet the required strength. For example, if the particle havinga diameter of 1 μm is interposed at the bonding interface, there is apossibility a void having a width in the direction along the bondinginterface of about 1000 μm may form.

In the present embodiment, a devisal is made to handle the semiconductorchip 11 without touching the activated front surface 11 a of thesemiconductor chip 11 when temporarily bonding the semiconductor chip 11to the substrate 20. In other words, the activated front surface 11 a ofthe semiconductor chip 11 attached to the adhesive sheet 1 and theactivated front surface 20 a of the substrate 20 are arranged to faceeach other, and the back surface 11 b of the semiconductor chip 11 ispushed through the adhesive sheet 1 to temporarily bond thesemiconductor chip 11 to the substrate 20, so that the temporary bondingis carried out while suppressing the production of particles.

Specifically, the temporary bonding of the plasma activated bonding iscarried out using a bonding apparatus 100 illustrated in FIGS. 2A and2B.

As illustrated in FIG. 2A, the bonding apparatus 100 includes anarrangement mechanism 110, an alignment mechanism 120, a pushingmechanism 130, a holding mechanism 140, a recognition mechanism 150, adepressurization mechanism 160, and a controller 170. In FIGS. 2A and2B, a direction perpendicular to an upper surface 112 a of a substratestage 112 is a Z direction, and two directions orthogonal to each otherwithin a plane parallel to the upper surface 112 a is an X direction anda Y direction.

The controller 170 entirely controls each unit of the bonding apparatus100.

The arrangement mechanism 110 arranges the activated front surface 11 aof each semiconductor chip 11 and the activated front surface 20 a ofthe substrate 20 so as to face each other with the back surface 11 b ofeach semiconductor chip 11 attached to the front surface 1 a of theadhesive sheet 1. For example, the arrangement mechanism 110 includes asheet stage 111 and the substrate stage 112.

The sheet stage 111 has a substantially ring shape when seen from the Zdirection in correspondence with the flat ring 2. The flat ring 2 ismounted on an upper surface 111 a of the sheet stage 111 with the frontsurface 11 a of each semiconductor chip 11 facing the lower side. Thesheet stage 111 may suction and hold the flat ring 2 by vacuumadsorption or electrostatic adsorption.

The substrate stage 112 has a planar shape including the substrate 20 onthe inner side when seen from the Z direction in correspondence with thesubstrate 20. The substrate 20 is mounted on the upper surface 112 a ofthe substrate stage 112 with the front surface 20 a facing the upperside. The substrate stage 112 may suction and hold the substrate 20 byvacuum adsorption or electrostatic adsorption.

The alignment mechanism 120 aligns the relative positions of thesemiconductor chip 11 and the substrate 20 under the control by thecontroller 170. For example, the alignment mechanism 120 includes drivemechanisms 121, 122. The drive mechanism 121 drives the sheet stage 111in the X direction, the Y direction, and a θ direction in accordancewith a command of a drive amount received from the controller 170. The θdirection is a rotating direction about the Z axis. The drive mechanism122 drives the substrate stage 112 in the X direction, the Y direction,and the θ direction in accordance with the command of the drive amountreceived from the controller 170.

It should be noted that, the alignment mechanism 120 may have aconfiguration in which one of the drive mechanism 121 or the drivemechanism 122 is omitted as long as the relative positions of thesemiconductor chip 11 and the substrate 20 can be aligned.

The depressurization mechanism 160 includes a vacuum pump 161 and vacuumexhaust paths 162, 163-1, 163-2.

The pushing mechanism 130 pushes the back surface 11 b of thesemiconductor chip 11 through the adhesive sheet 1 to closely attach theactivated front surface 11 a of the semiconductor chip 11 and theactivated front surface 20 a of the substrate 20 under the control bythe controller 170 (see FIG. 5A). The semiconductor chip 11 is therebytemporarily bonded to the substrate 20. The pushing mechanism 130 alsostrips the adhesive sheet 1 from the back surface 11 b of thesemiconductor chip 11 while maintaining the state in which the activatedfront surface 11 a of the semiconductor chip 11 is closely attached tothe activated front surface 20 a of the substrate 20 (see FIGS. 5B and5C). For example, the pushing mechanism 130 includes a pushing head 131,a head drive unit 132, a pin 135, and a pin drive unit 136.

The pushing head 131 has a pushing surface 131 f corresponding to theback surface 11 b of the semiconductor chip 11. The pushing surface 131f has a planar shape that does not interfere with the adjacentsemiconductor chip 11 including the back surface 11 b of thesemiconductor chip 11 to be pushed when seen from the Z direction. Thepushing surface 131 f may, for example, have a planar shape that is evenwith the back surface 11 b of the semiconductor chip 11. The head driveunit 132 drives the pushing head 131 in the Z direction under thecontrol by the controller 170. The pushing head 131 thus can push theback surface 11 b of the semiconductor chip 11 through the adhesivesheet 1.

The pushing head 131 has a buffer member 131 a on the pushing surface131 f. The buffer member 131 a buffers a force exerted on the backsurface 11 b of the semiconductor chip 11 when the pushing head 131pushes the back surface 11 b of the semiconductor chip 11 through theadhesive sheet 1, and at the same time, enables a uniform pressure to beexerted on the activated surface by absorbing the shift in planarity ofthe chip surface and the substrate surface. The buffer member 131 a canbe formed, for example, with an elastic body such as a rubber, and thelike.

The pushing head 131 has an suctioning structure 131 b for suctioningthe adhesive sheet 1 when the pushing head 131 pushes the back surface11 b of the semiconductor chip 11 through the adhesive sheet 1. Asillustrated in FIG. 2B, the suctioning structure 131 b is formed from agap of a hole 134 and the pin 135, and a communication path 137. The gapof the hole 134 and the pin 135 is communicated to the vacuum exhaustpath 162 through the communication path 137, and can be vacuum exhaustedby the vacuum pump 161 through the vacuum exhaust path 162. Thus, thesuctioning structure 131 b can vacuum-suction the adhesive sheet 1. Thesuctioning structure 131 b may be in other modes as long as the adhesivesheet 1 can be suctioned to the pushing surface 131 f of the pushinghead 131. For example, the suctioning structure 131 b may be formed by ahole communicated from the pushing surface 131 f to the communicationpath 137 separate from the hole, to which the pin 135 is inserted, andthe communication path 137.

The pin 135 can be changed between a state of being retracted toward thepushing head 131 side than the pushing surface 131 f and a state ofbeing projected out from the pushing surface 131 f. The pin 135 ismovable in the Z direction within the hole 134. The hole 134 is extendedin the Z direction in the pushing head 131. The pin drive unit 136 movesthe pin 135 in the Z direction along the hole 134 under the control bythe controller 170. The pin 135 is thereby retracted toward the pushinghead side 131 than the pushing surface 131 f or projected out from thepushing surface 131 f.

The holding mechanism 140 is arranged at a periphery of the pushingmechanism 130. The holding mechanism 140 holds the region at theperiphery of the region to be pushed with the pushing mechanism 130 inthe adhesive sheet 1. The holding mechanism 140 vacuum-suctions theregion at the periphery of the region to be pushed with the pushingmechanism 130 in the adhesive sheet 1. For example, the holdingmechanism 140 includes a plurality of sets of configurations forholding. The plurality of sets of configuration are arranged atpositions rotation symmetric with each other with respect to the pushingmechanism 130 when seen from the Z direction. Each of the plurality ofsets of configurations includes holding heads 141-1, 141-2, and headdrive units 142-1, 142-2.

The head drive units 142-1, 142-2 drive the holding heads 141-1, 141-2in the Z direction under the control by the controller 170. The holdingheads 141-1, 141-2 thus can vacuum-suction the adhesive sheet 1.

Each holding head 141-1, 141-2 includes a buffer member 141 a-1, 141 a-2at the surface 141 f that makes contact with the adhesive sheet 1. Thebuffer members 141 a-1, 141 a-2 buffer the force exerted on the backsurface 11 b of the semiconductor chip 11 when each holding head 141-1,141-2 vacuum-suctions the adhesive sheet 1. The buffer members 141 a-1,141 a-2 can be formed with an elastic body such as rubber, for example.

Each holding head 141-1, 141-2 includes a suctioning structure 141 b-1,141 b-2 for suctioning the adhesive sheet 1. The suctioning structure141 b-1, 141 b-2 is formed by a hole 144-1, 144-2 and a communicationpath 147-1, 147-2. The hole 144-1, 144-2 is communicated to the vacuumexhaust path 163-1, 163-2 by way of the communication path 147-1, 147-2,and can be vacuum exhausted by the vacuum pump 161 through the vacuumexhaust path 163-1, 163-2. The suctioning structures 141 b-1, 141 b-2thus can vacuum-suction the adhesive sheet 1.

The recognition mechanism 150 recognizes the semiconductor chip 11 andthe substrate 20. For example, the recognition mechanism 150 recognizeseach of the position of the semiconductor chip 11 and the position onthe substrate 20 where the semiconductor chip 11 is to be mounted. Therecognition mechanism 150 includes, for example, a lens barrel 151, acamera 152, and a ring illumination 153. The recognition mechanism 150illuminates an object (e.g., semiconductor chip 11 and substrate 20)with the ring illumination 153, and receives the reflected light withthe camera 152 through the lens barrel 151. The recognition mechanism150 thus can image the semiconductor chip 11 and the substrate 20, andprovide the image obtained by imaging to the controller 170.

For example, the recognition mechanism 150 can recognize the respectivepositions of the semiconductor chip 11 and the substrate 20 byrecognizing the respective contours of the semiconductor chip 11 and thesubstrate 20. Alternatively, for example, if an alignment mark is formedon each of the semiconductor chip 11 and the substrate 20, therecognition mechanism 150 can recognize the respective positions of thesemiconductor chip 11 and the substrate 20 by recognizing the respectivealignment marks of the semiconductor chip 11 and the substrate 20.

It should be noted that, the recognition mechanism 150 may include acoaxial illumination in place of the ring illumination 153. The coaxialillumination is, for example, arranged in the lens barrel 151 such thatthe optical axis is coaxial with the optical axis of the camera 152.Alternatively, the recognition mechanism 150 may include an illuminationarranged on a lower side (e.g., upper surface 112 a of the substrate112) in place of the ring illumination 153. For example, if thesubstrate 20 is the glass substrate, the illumination may be arranged ina region where the substrate 20 is to be mounted in the upper surface112 a of the substrate stage 112. If the substrate 20 is thesemiconductor substrate, for example, the illumination may be arrangedat the periphery of the region where the substrate 20 is to be mountedin the upper surface 112 a of the substrate stage 112.

Alternatively, the recognition mechanism 150 may include an IRillumination 154 illustrated with a chain dashed line in FIG. 2A inplace of the ring illumination 153. In this case, the camera 152 may bean IR camera. Thus, the recognition mechanism 150 can illuminate asubject (e.g., semiconductor chip 11 and substrate 20) with an IR light(infrared light) exit from the IR illumination 154, and receive atransmissive light (IR light) thereof with the camera 152 through thelens barrel 151.

Alternatively, although not illustrated, the recognition mechanism 150may include an upper and lower simultaneous recognition camera in placeof the camera 152. The upper and lower simultaneous recognition camerais inserted to a space between the plurality of semiconductor chips 11-1to 11-6 and the substrate 20 to be able to simultaneously image thesemiconductor chip 11 and the substrate 20. Thus, the recognitionmechanism 150 can simultaneously recognize the respective positions ofthe semiconductor chip 11 and the substrate 20.

In the bonding method of the semiconductor chip, steps illustrated inFIGS. 3A to 3C, FIGS. 4A to 4C, and FIGS. 5A to 5C are carried out asthe temporary bonding in the plasma activated bonding.

In the step illustrated in FIG. 3A, the arrangement mechanism 110arranges the activated front surfaces 11 a of the plurality ofsemiconductor chips 11-1 to 11-6 and the activated front surface 20 a ofthe substrate 20 so as to face each other. The back surfaces 11 b of theplurality of semiconductor chips 11-1 to 11-6 are attached to the frontsurface 1 a of the adhesive sheet 1.

At this time, the activated front surface 11 a of the semiconductor chip11 and the activated front surface 20 a of the substrate 20 arerespectively terminated with the hydroxyl group, but the water molecule(H—O—H) is often bonded to the hydroxyl group (—O—H) through hydrogenbonding, as illustrated in FIG. 6A. FIGS. 6A to 6D are viewsillustrating a mechanism of the plasma activated bonding. In FIGS. 6A to6D, a case in which the vicinity of the front surface 11 a is a silicondioxide film 11 i in the semiconductor chip 11 and a silicon region 11 jis arranged at a position deeper than the silicon dioxide film 11 i, andthe vicinity of the front surface 20 a is a silicon dioxide film 21 inthe substrate 20 and a silicon region 22 is arranged at a positiondeeper than the silicon dioxide film 21 is illustrated.

As illustrated in FIG. 3A, the recognition mechanism 150 recognizes theposition in the substrate 20 where the semiconductor chip 11 is to bemounted. For example, the recognition mechanism 150 illuminates thesubstrate 20 with the ring illumination 153, and receives the reflectedlight with the camera 152 through the lens barrel 151. Thus, therecognition mechanism 150 can image the substrate 20, and recognize theposition indicated with a broken line in FIG. 3A as the position in thesubstrate 20 where the semiconductor chip 11-4 is to be mounted. Therecognition mechanism 150 provides the recognition result to thecontroller 170.

In the step illustrated in FIG. 3B, the holding mechanism 140 holds theregion at the periphery of the region to be pushed by the pushingmechanism 130 in the adhesive sheet 1. For example, the controller 170can cause the suctioning structures 141 b-1, 141 b-2 to be in avacuum-suctionable state, and controls the head drive units 142-1, 142-2to move the holding heads 141-1, 141-2 in the −Z direction (see FIG.2A). If the semiconductor chip 11-4 is selected as the semiconductorchip to be pushed among the plurality of semiconductor chips 11-1 to11-6, the region at the periphery of the region corresponding to thesemiconductor chip 11-4 in the adhesive sheet 1 is vacuum-suctioned bythe holding mechanism 140. In FIG. 3B, a case of vacuum-suctioning theregions corresponding to the semiconductor chips 11-2, 11-3, 11-5, 11-6in the adhesive sheet 1 with the holding heads 141-1, 141-2 isillustrated, but the region is not limited to the regions correspondingto the semiconductor chips 11-2, 11-3, 11-5, 11-6 as long as it is atthe periphery of the region corresponding to the semiconductor chip11-4. Thus, the deflection of the region to be pushed by the pushingmechanism 130 in the adhesive sheet 1 can be controlled.

In the step illustrated in FIG. 3C, the recognition mechanism 150recognizes the position to be pushed by the pushing mechanism 130 in theadhesive sheet 1. For example, the recognition mechanism 150 illuminatesthe adhesive sheet 1 and the semiconductor chip 11-4 with the ringillumination 153, and receives the reflected light with the camera 152through the lens barrel 151. Thus, the recognition mechanism 150 canimage the adhesive sheet 1 and the semiconductor chip 11-4, andrecognize the position indicated with a broken line in FIG. 3C as theposition to be pushed by the pushing mechanism 130 in the adhesive sheet1. The recognition mechanism 150 provides the recognition result to thecontroller 170.

It should be noted that, the position (absolute position or the relativeposition with respect to the substrate 20) of the adhesive sheet 1 andthe semiconductor chop 11-4 has a possibility of shifting when theholding mechanism 140 vacuum-suctions the adhesive sheet 1 in the stepillustrated in FIG. 3B, but the recognized position is less likely to besubjected to the influence of shift since the position of after theshift can be recognized in the step illustrated in FIG. 3C.

In the step illustrated in FIG. 4A, the pushing mechanism 130vacuum-suctions the adhesive sheet 1. For example, the controller 170obtains the drive amount of the sheet stage 111 for positioning theposition to be pushed by the pushing mechanism 130 in the adhesive sheet1 to under the pushing mechanism 130 and provides the same to the drivemechanism 121 of the alignment mechanism 120 according to therecognition result by the recognition mechanism 150. The drive mechanism121 drives the sheet stage 111 according to the command of the driveamount. The position to be pushed by the pushing mechanism 130 in theadhesive sheet 1 is thereby positioned under the pushing mechanism 130.The controller 170 causes the suctioning structure 131 b to be in avacuum-suctioning state, and controls the head drive unit 132 to movethe pushing head 131 in the −Z direction (see FIG. 2A). Thus, theadhesive sheet 1 is vacuum-suctioned to the pushing surface 131 f of thepushing head 131. In this case, the pin 135 is maintained in a stateretracted toward the pushing head 131 side from the pushing surface 131f.

In the step illustrated in FIG. 4B, the recognition mechanism 150recognizes the position (absolute position or relative position withrespect to the substrate 20) of the semiconductor chip 11. For example,the recognition mechanism 150 illuminates the semiconductor chip 11-4with the ring illumination 153, and receives the reflected light withthe camera 152 through the lens barrel 151. The recognition mechanism150 can image the semiconductor chip 11-4, and recognize the position ofthe semiconductor chip 11. The recognition mechanism 150 provides therecognition result to the controller 170.

It should be noted that, although the position (absolute position or therelative position with respect to the substrate 20) of the adhesivesheet 1 and the semiconductor chop 11-4 has a possibility of shiftingwhen the pushing mechanism 130 vacuum-suctions the adhesive sheet 1 inthe step illustrated in FIG. 4A, the position to be recognized is lesslikely to be subjected to the influence of shift since the position ofafter the shift can be recognized in the step illustrated in FIG. 4B.

In the step illustrated in FIG. 4C, the alignment mechanism 120 alignsthe relative positions of the semiconductor chip 11 and the substrate20. For example, the controller 170 obtains the drive amount foralignment based on the recognition result received in the stepillustrated in FIG. 3A and the recognition result received in the stepillustrated in FIG. 4B. For example, the controller 170 obtains adifference ΔL (see FIG. 4B) of the position in the substrate 20 wherethe semiconductor chip 11-4 is to be mounted and the position of thesemiconductor chip 11-4 for each of the X direction, the Y direction,and the θ direction. The controller 170 obtains the drive amount of eachof the X direction, the Y direction, and the θ direction so as to cancelthe difference ΔL, and provides the same to the drive mechanism 122 ofthe alignment mechanism 120. The drive mechanism 122 drives thesubstrate stage 112 according to the command of the drive amount. Thus,the position of the semiconductor chip 11-4 and the position in thesubstrate 20 where the semiconductor chip 11-4 is to be mounted arerelatively aligned.

In the step illustrated in FIG. 5A, the pushing mechanism 130 pushes theback surface 11 b of the semiconductor chip 11 through the adhesivesheet 11. For example, the controller 170 controls the head drive unit132 to move the pushing head 131 further in the −Z direction (see FIG.2A). Thus, the pushing head 131 pushes the back surface 11 b of thesemiconductor chip 11-4 through the adhesive sheet 1, and closelyattaches the activated front surface 11 a of the semiconductor chip 11-4to the activated front surface 20 a of the substrate 20. Thesemiconductor chip 11-4 is thereby temporarily bonded to the substrate20. The adhesive sheet 1 is also elastically deformed thus generating atensile force between the region pushed with the pushing mechanism 130and the region held with the holding mechanism 140 (holding heads 141-1,141-2).

At this time, as illustrated in FIG. 6B, the activated front surface 11a of the semiconductor chip 11 and the activated front surface 20 a ofthe substrate 20 are temporarily bonded as the water molecules (H—O—H)bonded to the hydroxyl group are bonded to each other by hydrogenbonding.

In the step illustrated in FIG. 5B, the pushing mechanism 130 strips theadhesive sheet 1 from the back surface 11 b of the semiconductor chip 11while maintaining the state in which the activated front surface 11 a ofthe semiconductor chip 11 is closely attached to the activated frontsurface 20 a of the substrate 20. For example, the controller 170controls the pin drive unit 136 to enable the pin 135 to push the backsurface 11 b of the semiconductor chip 11 through the adhesive sheet 1.The controller 170 controls the depressurization mechanism 160 torelease the vacuum adsorption of the suctioning structure 131 b. Thecontroller 170 controls the head drive unit 132 to move the pushing head131 in the +Z direction while controlling the pin drive unit 136 tomaintain the state in which the pin 135 pushes the back surface 11 b ofthe semiconductor chip 11 through the adhesive sheet 1 (see FIG. 2A). Inother words, as the pushing head 131 moves in the +Z direction away fromthe back surface 11 b of the semiconductor chip 11, the pin 135 projectsout from the pushing surface 131 f while maintaining the state ofpushing the back surface 11 b of the semiconductor chip 11 through theadhesive sheet 1.

At this time, the adhesion force of the adhesive formed on the frontsurface 1 a of the adhesive sheet 1 is lowered in the step illustratedin FIG. 5B. Thus, the adhesive sheet 1 is easily stripped from theperiphery of the region pushed with the pin 135 in the back surface 11 bof the semiconductor chip 11-4 by the tensile force between the regionpushed with the pushing mechanism 130 in the adhesive sheet 1 and theregion held by the holding mechanism 140.

In the step illustrated in FIG. 5C, the pushing mechanism 130 completesthe stripping of the adhesive sheet 1 from the back surface 11 b of thesemiconductor chip 11. For example, the controller 170 controls the pindrive unit 136 to move the pin 135 in the +Z direction, and releases thestate of pushing the back surface 11 b of the semiconductor chip 11through the adhesive sheet 1. The controller 170 may control the pindrive unit 136 to have the pin 135 in the state retracted toward thepushing head 131 side than the pushing surface 131 f.

Consider a case of releasing the pushing by the pushing head 131 torelease, all at once, the pushing against the back surface 11 b of thesemiconductor chip 11 without having the pin 135 push the back surface11 b of the semiconductor chip 11 through the adhesive sheet 1. In thiscase, substantially the entire surface of the back surface 11 b of thesemiconductor chip 11-4 is adhered to the adhesive sheet 1, and the areaof the region adhered to the adhesive sheet 1 in the back surface 11 bof the semiconductor chip 11-4 is large. Thus, the force of pulling thesemiconductor chip 11-4 upward with the tensile force and the adhesiveforce of the adhesive sheet 1 may become greater than the force ofpulling the semiconductor chip 11-4 downward with the force of thetemporary bonding of the semiconductor chip 11-4 to the substrate 20.Thus, the state in which the semiconductor chip 11-4 is temporarilybonded to the substrate 20 may not be maintained and the semiconductorchip 11-4 may be stripped from the substrate 20.

On the contrary, in the present embodiment, the area of the regionadhered to the adhesive sheet 1 in the back surface 11 b of thesemiconductor chip 11-4 is small in the step illustrated in FIG. 5C.Thus, the force of pulling the semiconductor chip 11-4 downward with theforce of the temporarily bonding of the semiconductor chip 11-4 to thesubstrate 20 can easily overcome the force of pulling the semiconductorchip 11-4 upward with the tensile force and the adhesive force of theadhesive sheet 1. The stripping of the adhesive sheet 1 from the backsurface 11 b of the semiconductor chip 11 thus can be completed whilemaintaining the state in which the semiconductor chip 11-4 istemporarily bonded to the substrate 20.

Similarly, other semiconductor chips 11-1 to 11-3, 11-5, 11-6 attachedto the adhesive sheet 1 can be temporarily bonded to the substrate 20 bycarrying out the steps of FIGS. 3A to 3C, FIGS. 4A to 4C, and FIGS. 5Ato 5C.

In the bonding method of the semiconductor chip, the step illustrated inFIG. 5D is then carried out as the actual bonding in the plasmaactivated bonding.

In the step illustrated in FIG. 5D, the semiconductor chip 11 is heatedwith the back surface 11 b of the semiconductor chip 11 physicallypressurized. For example, the back surface 11 b of the semiconductorchip 11 is thermally brought into contact with the hot plate through abuffer sheet (made from a heat resisting material), and heated at lowerthan or equal to 250° C., for example. At the same time, the substrate20 may be brought into contact with a different hot plate from the backsurface 20 b side and heated at lower than or equal to 250° C. Theheating temperature is desirably appropriately (e.g., suitably) setaccording to the material and the structure of the semiconductor chipand the substrate, and for example, can be higher than or equal to 1000°C. if between materials having the same coefficient of thermalexpansion, for example, so that the time for the bonding process to bedescribed later can be reduced and the productivity can be enhanced. Inthe bonding between materials having different coefficients of thermalexpansion such as the silicon and the III-V group semiconductor, theresidual heat stress due to the lowering of the temperature after thebonding process is terminated reduces, and hence the temperature isrecommended to be as low as possible, and desirably, lower than or equalto 150° C.

In the process of pressurization and heating described above, at thebonding interface of the semiconductor chip 11 and the substrate 20, thewater molecules (H—O—H) pass from the bonding interface, and thehydrogen bonding of the water molecules (H—O—H) change to the hydrogenbonding of the hydroxyl groups (—O—H) or change to the covalent bondingthrough an oxygen atom (—O—), as illustrated in FIG. 6C. The bondinginterface width of the front surface 11 a of the semiconductor chip 11and the front surface 20 a of the substrate 20 is thus narrowed from G1to G2 (<G1). As the bonding process advances, at the bonding interfaceof the semiconductor chip 11 and the substrate 20, the water molecules(H—O—H) pass from the hydrogen bonding of the hydroxyl groups (—O—H)thus changing to the covalent bonding through the oxygen atom (—O—), asillustrated in FIG. 6D. The bonding interface width of the front surface11 a of the semiconductor chip 11 and the front surface 20 a of thesubstrate 20 is thus narrowed from G2 to G3 (<<G2), and the oxide films11 i, 21 of the front surfaces are actually bonded in a substantiallyintegrated manner.

It should be noted that the actual bonding can be performed withoutphysical pressure depending on the material of the substrate and thematerial of the semiconductor chip. In this case, in the stepillustrated in FIG. 5D, the semiconductor chip 11 can be heated withoutphysically pressuring the back surface 11 b of the semiconductor chip11. For example, if the semiconductor chip is formed of In—P materialsystem, the actual bonding can be performed with heating at about 200°C. without physical pressure. In this way, whether or not physicalpressure is necessary in the actual bonding steps changes depending onvarious conditions such as materials or chip sizes.

As described above, in the embodiment, the front surface 11 a of thesemiconductor chip 11 and the front surface 20 a of the substrate 20 arerespectively activated by plasma thus closely attaching thesemiconductor chip 11 to the substrate 20 in the boding method of thesemiconductor chip. Thus, the semiconductor chip 11 can be temporarilybonded on the substrate 20 at a normal temperature without interposingthe solder bump, whereby the semiconductor chip 11 can be mounted on thesubstrate 20 while suppressing the thermal deformation of thesemiconductor chip 11. As a result, the alignment accuracy of thebonding of the semiconductor chip at the time of temporary bonding canbe easily enhanced. Although the semiconductor chip 11 is subsequentlyheated and pressurized to be actually bonded to the substrate 20, thealignment accuracy of the bonding of the semiconductor chip in theactual bonding can be easily enhanced since the bonding position of thesemiconductor chip 11 on the substrate 20 can be substantially fixedwith the temporary bonding.

In the embodiment, the semiconductor chip 11 can be bonded onto thesubstrate 20 without interposing the solder bump in the bonding methodof the semiconductor chip, and hence the arrangement density of the padelectrodes in the semiconductor chip 11 can be easily enhanced. Forexample, the arrangement pitch of the pad electrodes in thesemiconductor chip may be about a few μm. The mounting density of thesemiconductor chip 11 thus can be easily enhanced.

Furthermore, in the embodiment, the activated front surface 11 a of thesemiconductor chip 11 attached to the adhesive sheet 1 and the activatedfront surface 20 a of the substrate 20 are arranged to face each other,and the back surface 11 b of the semiconductor chip 11 is pushed throughthe adhesive sheet 1 to temporarily bond the semiconductor chip 11 tothe substrate 20 in the bonding method of the semiconductor chip. Theadhesive sheet 1 is stripped from the back surface 11 b of thesemiconductor chip 11 while maintaining the state in which the activatedfront surface 11 a of the semiconductor chip 11 is closely attached tothe activated front surface 20 a of the substrate 20. Thus, thesemiconductor chip 11 can be handled without touching the activatedfront surface 11 a of the semiconductor chip 11 when temporarily bondingthe semiconductor chip 11 to the substrate 20, and the temporary bondingcan be completed while suppressing the production of particles.

In the embodiment, the activated front surfaces 11 a of the plurality ofsemiconductor chips 11 and the activated front surface 20 a of thesubstrate 20 are arranged to face each other with the back surfaces 11 bof the plurality of semiconductor chips 11 attached to the adhesivesheet 1 in the bonding method of the semiconductor chip. The process ofpushing the back surface 11 b of the semiconductor chip 11 selected fromthe plurality of semiconductor chips 11 to closely attach the activatedfront surface 11 a of the semiconductor chip 11 to the activated frontsurface 20 a of the substrate 20, and stripping the adhesive sheet 1from the back surface 11 b of the semiconductor chip 11 whilemaintaining the closely attached state is sequentially carried out foreach semiconductor chip 11. Thus, the temporary bonding of the pluralityof semiconductor chips 11 to the substrate 20 can be efficiently carriedout while suppressing the production of particles.

Moreover, in the embodiment, the interval of the plurality ofsemiconductor chips 11 on the adhesive sheet 1 is widened beforearranging the activated front surfaces 11 a of the plurality ofsemiconductor chips 11 and the activated front surface 20 a of thesubstrate 20 so as to face each other in the bonding method of thesemiconductor chip. For example, the interval of the plurality ofsemiconductor chips 11 on the adhesive sheet 1 is made wider than thethickness of the semiconductor chip 11. Thus, the side surface 11 c ofthe semiconductor chip 11 to be pushed is less likely to make contactwith the side surface 11 c of the adjacent semiconductor chip 11 and theproduction of particles can be suppressed in the step of pushing thesemiconductor chip 11 through the adhesive sheet 1.

In the embodiment, the step of pushing the back surface 11 b of thesemiconductor chip 11 through the adhesive sheet 1 is carried out withthe region at the periphery of the region to be pushed in the adhesivesheet 1 held by the holding mechanism 140 in the bonding method of thesemiconductor chip. Thus, the back surface 11 b of the semiconductorchip 11 can be pushed through the adhesive sheet 1 with the deflectionof the adhesive sheet 1 appropriately controlled, so that the strippingof the adhesive sheet 1 from the back surface 11 b of the semiconductorchip 11 can be subsequently carried appropriately.

In the embodiment, the pushing mechanism 130 pushes the back surface 11b of the semiconductor chip 11 through the adhesive sheet 1 to closelyattach the activated front surface 11 a of the semiconductor chip 11 tothe activated front surface 20 a of the substrate 20 in the bondingapparatus of the semiconductor chip. The pushing mechanism 130 alsostrips the adhesive sheet 1 from the back surface 11 b of thesemiconductor chip 11 while maintaining the state in which the activatedfront surface 11 a of the semiconductor chip 11 is closely attached tothe activated front surface 20 a of the substrate 20. Thus, thesemiconductor chip 11 can be handled without touching the activatedfront surface 11 a of the semiconductor chip 11 when temporarily bondingthe semiconductor chip 11 to the substrate 20, and the temporary bondingcan be carried out while suppressing the production of particles.

In the embodiment, the pushing head 131 includes the pushing surface 131f in correspondence with the back surface 11 b of the semiconductor chip11 in the pushing mechanism 130 of the bonding apparatus of thesemiconductor chip. The back surface 11 b of the semiconductor chip 11thus can be pushed at a substantially uniform force within the plane.

In the embodiment, the pin 135 can be changed between the state of beingretracted toward the pushing head 131 side than the pushing surface 131f and the state of being projected out from the pushing surface 131 f inthe pushing mechanism 130 of the bonding apparatus of the semiconductorchip. Thus, the pin 135 is retracted toward the pushing head 131 sidethan the pushing surface 131 f when the pushing head 131 pushes the backsurface 11 b of the semiconductor chip 11 through the adhesive sheet 1,so that the pin 135 does not become a hindrance in the pushing operationof the pushing head 131. The pin 135 is projected out from the pushingsurface 131 f when the pushing by the pushing head 131 is released, sothat the stripping of the adhesive sheet 1 from the back surface 11 b ofthe semiconductor chip 11 can be easily completed while maintaining thestate in which the semiconductor chip 11-4 is temporarily bonded to thesubstrate 20.

In the embodiment, the pushing mechanism 130 pushes the back surface 11b of the semiconductor chip 11 through the adhesive sheet 1 toward thesubstrate 20 side with the region at the periphery of the region to bepushed by the pushing mechanism 130 in the adhesive sheet 1 held by theholding mechanism 140 in the bonding apparatus of the semiconductorchip. Thus, the back surface 11 b of the semiconductor chip 11 can bepushed through the adhesive sheet 1 with the deflection of the adhesivesheet 1 appropriately controlled, so that the stripping of the adhesivesheet 1 from the back surface 11 b of the semiconductor chip 11 can besubsequently carried appropriately.

In the embodiment, the alignment mechanism 120 positions the region tobe pushed with the pushing mechanism 130 in the adhesive sheet 1 basedon the recognition result of the recognition mechanism 150 in thebonding apparatus of the semiconductor chip. The alignment mechanism 120aligns the relative positions of the semiconductor chip 11 and thesubstrate 20 based on the recognition result of the recognitionmechanism 150. The pushing mechanism 130 pushes the back surface 11 b ofthe semiconductor chip 11 through the adhesive sheet 1 with the relativepositions of the semiconductor chip 11 and the substrate 20 aligned.Thus, the pushing mechanism 130 can accurately push, and each of theplurality of semiconductor chips 11 attached to the adhesive sheet 1 canbe mounted on appropriate positions on the substrate 20.

It should be noted that, in the step illustrated in FIG. 1C, forexample, the interval of the adjacent semiconductor chips 11-1 to 11-6can be widened by decimating the plurality of semiconductor chips 11-1to 11-6. For example, the interval of the adjacent semiconductor chips11-1 to 11-6 can be widened to an extent corresponding to one chip widthby decimating the semiconductor chips 11-2, 11-4, 11-6 from theplurality of semiconductor chips 11-1 to 11-6. However, particles mayproduce when decimating the semiconductor chips 11-2, 11-4, 11-6.Therefore, after the decimation, the washing (e.g., ultrasonic washing)and the drying processes are sequentially carried out with respect tothe front surface 11 a of each semiconductor chip 11 with eachsemiconductor chip 11 attached to the adhesive sheet 11. The particlesattached to the front surface 11 a of each semiconductor chip 11 arethereby removed.

The timing to carry out the step (step illustrated in FIG. 1D) ofwidening the interval of the plurality of semiconductor chips 11-1 to11-6 merely needs to be before the step (step illustrated in FIG. 3A) ofarranging the semiconductor chip 11 and the substrate 20 to face eachother, and is not limited to after the step illustrated in FIG. 1B. Forexample, the timing to carry out the step (step illustrated in FIG. 1D)of widening the interval of the plurality of semiconductor chips 11-1 to11-6 may be after the step illustrated in FIG. 1D and before the stepillustrated in FIG. 3A.

In the bonding method of the semiconductor chip, the steps illustratedin FIGS. 7A to 7D may be carried out in place of the steps illustratedin FIGS. 1A and 1B.

In the step illustrated in FIG. 7A, the semiconductor substrate 10similar to that prepared in the step illustrated in FIG. 1A is prepared.The front surface 10 a of the prepared semiconductor substrate 10 isattached to a front surface 3 a of an adhesive sheet (dicing tape) 3. Inother words, the semiconductor substrate 10 is attached to the adhesivesheet 3 with the back surface 10 b exposed (face-down state). Theadhesive sheet 3 has an adhesive applied on the front surface 3 a. Theadhesive may be, for example, an adhesive having UV curability. Theadhesive sheet 3 is stretched within a frame of an annular flat ring 4and fixed to the flat ring 4. The adhesive sheet 3 is, for example, madefrom a transparent resin having light permeability.

In the step illustrated in FIG. 7B, the semiconductor substrate 10 isdivided and singulated to a plurality of semiconductor chips 11-1 to11-6. For example, the semiconductor substrate 10 is dicing processedalong the dicing line. The dicing process may be carried out by cuttingwith the dicing blade along the dicing line. Alternatively, the dicingprocess may be carried out by emitting laser along the dicing line toperform laser processing.

Since the semiconductor substrate 10 is attached to the adhesive sheet 3with the back surface 10 b exposed (face-down state), the particles canbe prevented from attaching to the front surface 11 a of thesemiconductor chip 11.

Thereafter, the UV irradiation is carried out on the adhesive sheet 3from the back surface 3 b side to cure the adhesive applied on the frontsurface 3 a of the adhesive sheet 3 thus lowering the adhesion forcethereof.

The washing (e.g., ultrasonic washing) and the drying processes may besequentially carried out with respect to the back surface 11 b of eachsemiconductor chip 11 with each semiconductor chip 11 attached to theadhesive sheet 3. Thus, if the particles are attached to the backsurface 11 b of each semiconductor chip 11, the attached particles canbe removed.

In the step illustrated in FIG. 7C, the front surface 1 a of theadhesive sheet 1 is attached to the back surfaces 11 b of the pluralityof singulated semiconductor chips 11-1 to 11-6. In this case, theadhesion force of the adhesive formed on the front surface 3 a of theadhesive 3 is lowered in the step illustrated in FIG. 7B. Thus, theplurality of semiconductor chips 11-1 to 11-6 are easily transferredfrom the adhesive sheet 3 to the adhesive sheet 1. In other words, thesemiconductor substrate 10 is attached to the adhesive sheet 1 with thefront surface 10 a exposed (face-up state).

In the step illustrated in FIG. 7D, the adhesive sheet 1, to which theplurality of semiconductor chips 11-1 to 11-6 are transferred, isstretched within the frame of the annular flat ring 2 and fixed to theflat ring 2.

Thereafter, the step illustrated in FIG. 1C and the subsequent steps arecarried out.

The dicing process of the semiconductor substrate 10 is carried out withthe semiconductor substrate 10 faced down, so that the attachment of theparticles produced at the time of the dicing process to the frontsurface 11 a of each singulated semiconductor chip 11 can be furtherreduced, and the particles can be effectively suppressed frominterposing at the bonding interface at the time of the temporarybonding of the semiconductor chip 11 to the substrate 20.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

(Additional Note 1)

A bonding method of a semiconductor chip comprising:

arranging an activated front surface of a semiconductor chip and anactivated front surface of a substrate so as to face each other with aback surface of the semiconductor chip attached to a sheet;

pushing the back surface of the semiconductor chip through the sheet toclosely attach the activated front surface of the semiconductor chip andthe activated front surface of the substrate; and

stripping the sheet from the back surface of the semiconductor chipwhile maintaining the state in which the activated front surface of thesemiconductor chip is closely attached to the activated front surface ofthe substrate.

(Additional Note 2)

The bonding method of the semiconductor chip according to additionalnote 1, further comprising

irradiating the front surface of the semiconductor chip with a plasma oran energy beam with the back surface of the semiconductor chip attachedto the sheet to activate the front surface before the arranging step.

(Additional Note 3)

The bonding method of the semiconductor chip according to additionalnote 1, further comprising

heating the semiconductor chip with the back surface of thesemiconductor chip pressurized after the stripping.

(Additional Note 4)

The bonding method of the semiconductor chip according to additionalnote 1, wherein

a vicinity of the front surface of the semiconductor chip is made of amaterial having any one of a silicon, a silicon oxide, a III-V groupsemiconductor, or an oxide of the III-V group semiconductor as a maincomponent.

(Additional Note 5)

The bonding method of the semiconductor chip according to additionalnote 1, wherein

the substrate includes a semiconductor substrate or a glass substrate.

(Additional Note 6)

The bonding method of the semiconductor chip according to additionalnote 5, wherein

a vicinity of the front surface of the semiconductor substrate is madeof a material having a silicon or a silicon oxide as a main component.

(Additional Note 7)

The bonding method of the semiconductor chip according to additionalnote 1, wherein

the front surface of the semiconductor chip has planarity of smallerthan or equal to 1 nm.

(Additional Note 8)

The bonding method of the semiconductor chip according to additionalnote 1, wherein

the front surface of the substrate has planarity of smaller than orequal to 1 nm.

(Additional Note 9)

The bonding method of the semiconductor chip according to additionalnote 1, wherein

the arranging includes arranging activated front surfaces of a pluralityof semiconductor chips and the activated front surface of the substrateso as to face each other with back surfaces of the plurality ofsemiconductor chips attached to the sheet,

the closely attaching includes pushing the back surface of thesemiconductor chip selected from the plurality of semiconductor chipsthrough the sheet to closely attach the activated front surface of theselected semiconductor chip and the activated front surface of thesubstrate, and

the stripping includes stripping the sheet from the back surface of theselected semiconductor chip.

(Additional Note 10)

The bonding method of the semiconductor chip according to additionalnote 9, further comprising

widening an interval of the plurality of semiconductor chips before thearranging.

(Additional Note 11)

The bonding method of the semiconductor chip according to additionalnote 10, wherein

the widening includes widening the interval of the plurality ofsemiconductor chips to greater than a thickness of the semiconductorchip.

(Additional Note 12)

The bonding method of the semiconductor chip according to additionalnote 9, wherein

the closely attaching includes pushing the back surface of the selectedsemiconductor chip through the sheet while holding a region at aperiphery of the selected semiconductor chip in the sheet.

(Additional Note 13)

The bonding method of the semiconductor chip according to additionalnote 12, wherein

the holding includes suctioning and holding the region at the peripheryof the selected semiconductor chip in the sheet.

(Additional Note 14)

The bonding method of the semiconductor chip according to additionalnote 9, further comprising:

attaching a front surface of a second semiconductor substrate to asecond sheet;

dividing the second semiconductor substrate to singulate to theplurality of semiconductor chips; and

attaching the back surfaces of the singulated plurality of semiconductorchips to the sheet, and transferring the plurality of semiconductorchips from the second sheet to the sheet.

(Additional Note 15)

A bonding apparatus of a semiconductor chip comprising:

an arrangement mechanism configured to arrange an activated frontsurface of a semiconductor chip and an activated front surface of asubstrate so as to face each other with a back surface of thesemiconductor chip attached to a sheet; and

a pushing mechanism configured to push the back surface of thesemiconductor chip through the sheet to closely attach the activatedfront surface of the semiconductor chip to the activated front surfaceof the substrate, and strip the sheet from the back surface of thesemiconductor chip while maintaining the state in which the activatedfront surface of the semiconductor chip is closely attached to theactivated front surface of the substrate.

(Additional Note 16)

The bonding apparatus of the semiconductor chip according to additionalnote 15, wherein

the pushing mechanism includes,

a pushing head including a pushing surface corresponding to the backsurface of the semiconductor chip, and

a pin configured to be changed between a state retracted toward thepushing head side than the pushing surface and a state projected outfrom the pushing surface.

(Additional Note 17)

The bonding apparatus of the semiconductor chip according to additionalnote 16, wherein

the pushing head includes a buffer member on the pushing surface.

(Additional Note 18)

The bonding apparatus of the semiconductor chip according to additionalnote 16, wherein

the pushing head has an suctioning structure of suctioning the sheet.

(Additional Note 19)

The bonding apparatus of the semiconductor chip according to additionalnote 15, further comprising a holding mechanism arranged at a peripheryof the pushing mechanism, wherein

the pushing mechanism pushes the back surface of the semiconductor chipthrough the sheet toward the substrate side with a region at a peripheryof the region to be pushed with the pushing mechanism in the sheet heldby the holding mechanism.

(Additional Note 20)

The bonding apparatus of the semiconductor chip according to additionalnote 15, further comprising:

a recognition mechanism configured to recognize the substrate and thesemiconductor chip; and

an alignment mechanism configured to align relative positions of thesemiconductor chip and the substrate based on a recognition result ofthe recognition mechanism, wherein

the pushing mechanism pushes the back surface of the semiconductor chipthrough the sheet with the relative positions of the semiconductor chipand the substrate aligned.

What is claimed is:
 1. A mounting apparatus for a chip comprising: anarrangement mechanism comprising a sheet stage and a substrate stage,wherein the sheet stage immovably fixes a sheet where a chip isdisposed, the substrate stage is disposed on a first side of the sheet,and the substrate stage holds a substrate; a pushing mechanism disposedon a second side of the sheet, the second side being opposite to thefirst side, the pushing mechanism being capable of pushing a firstregion of the sheet immovably fixed by the sheet stage in a direction ofthe first side, and the first region being a region corresponding to thechip; and a holding mechanism disposed on the second side of the sheet,the holding mechanism being disposed at a periphery of the pushingmechanism, the holding mechanism being capable of holding a secondregion of the sheet immovably fixed by the sheet stage, and the secondregion being a region at a periphery of the first region when seen in adirection perpendicular to a front surface of the substrate, wherein thepushing mechanism pushes the first region toward the second side toattach the chip to the substrate in a first period, lowers an adhesionforce of the first region to a back surface of the chip in a secondperiod later than the first period, further lowers an adhesion force ofthe first region to the back surface of the chip in a third period laterthan the second period, releases an adhesion force of the first regionto the back surface of the chip in a fourth period later than the thirdperiod, and strips the sheet from the back surface of the chip.
 2. Themounting apparatus according to claim 1, wherein: the arrangementmechanism is configured to arrange a front surface of the chip and thefront surface of the substrate such that the front surface of the chipand the front surface of the substrate face each other in a state wherethe back surface of the chip is attached to the sheet, the holdingmechanism is capable of moving relative to the sheet stage in adirection that is not perpendicular to the front surface of thesubstrate so as to hold the second region of the sheet, and the pushingmechanism is configured to push the back surface of the chip through thefirst region of the sheet so that the front surface of the chip isbrought close to the front surface of the substrate.
 3. The mountingapparatus according to claim 2, wherein the pushing mechanism isconfigured to release itself from the first region of the sheet so as tostrip the sheet from the back surface of the chip.
 4. The mountingapparatus according to claim 2, wherein the pushing mechanism comprises:a pushing head comprising a pushing surface corresponding to the backsurface of the chip, and a pin configured to retract from the pushingsurface and to project from the pushing surface.
 5. The mountingapparatus according to claim 4, wherein the pushing head furthercomprises a buffer member on the pushing surface.
 6. The mountingapparatus according to claim 4, wherein the pushing mechanism furthercomprises a driving unit which causes the pin to retract from thepushing surface and to project from the pushing surface.
 7. The mountingapparatus according to claim 1, further comprising: a recognitionmechanism configured to recognize the substrate and the chip; and analignment mechanism configured to align relative positions of the chipand the substrate based on a recognition result of the recognitionmechanism, wherein the pushing mechanism pushes the back surface of thechip through the first region of the sheet with the relative positionsof the chip and the substrate aligned.
 8. The mounting apparatusaccording to claim 1, wherein the holding mechanism comprises asuctioning structure which suctions the second region of the sheet. 9.The mounting apparatus according to claim 1, wherein the substrate stageand the sheet stage are driven independently from each other.
 10. Themounting apparatus according to claim 9, wherein the sheet stage isconfigured to hold a flat ring which can immovably fix, relative to thesheet stage, the sheet where the chip is attached.
 11. The mountingapparatus according to claim 2, wherein the chip is arranged face downabove the substrate by the arrangement mechanism.
 12. The mountingapparatus according to claim 7, wherein the recognition mechanismcomprises an illumination device and a camera.
 13. The mountingapparatus according to claim 12, wherein the illumination device isarranged on an opposite side of the pushing mechanism across thesubstrate stage.
 14. The mounting apparatus according to claim 12,wherein the illumination device is an infrared (IR) illumination device.15. The mounting apparatus according to claim 1, wherein: the sheetstage is capable of immovably fixing an outer region of the sheet, andthe holding mechanism is capable of holding the second region which ison an inner side of the sheet stage.
 16. The mounting apparatusaccording to claim 1, further comprising: a controller which controls adrive of the pushing mechanism and a drive of the holding mechanismindependently from each other.
 17. The mounting apparatus according toclaim 16, wherein the controller controls a height of the holdingmechanism from the substrate stage to be lower than a height of thepushing mechanism from the substrate stage.
 18. The mounting apparatusaccording to claim 16, wherein the controller controls, after the sheetis held by the holding mechanism, the pushing mechanism to touch thesheet so that the first region is pushed.
 19. The mounting apparatusaccording to claim 1, wherein the pushing mechanism pushes the firstregion which includes a point position, the point position correspondingto a center of a pushing portion of the pushing mechanism.
 20. Themounting apparatus according to claim 1, wherein the mounting apparatusshifts respective positions of the pushing mechanism and the holdingmechanism relative to the sheet stage along a plane that intersects apushing direction of the pushing mechanism, before or after the pushingmechanism pushes the sheet.